In holographic recording that uses holography to record information into a recording medium, a laser beam from, for example, a laser diode is split into an object beam and a reference beam, and information is recorded into a holographic recording medium by an interference pattern formed by the reference beam and an information beam obtained by modulating the object beam.
When reproducing the recorded information, the reference beam is irradiated to the holographic recording medium, whereby the information is reproduced by the diffraction from the interference pattern.
As one of the above-described holographic recording media, there is a holographic recording medium described in, for example, Japanese Patent Laid-Open Publication No. 2002-251745, in which two-dimensional information pages used for recording two-dimensional patterns based on the information to be recorded, each capable of holographic recording and comprising multiple pixels, are provided in multiplexed form.
To address the above-described two-dimensional information pages in which two-dimensional patterns are recorded, in the information recording medium described in Japanese Patent Laid-Open Publication No. 2002-251745, address information that is holographic information is recorded at a specific site in each of the two-dimensional information pages.
In the optical information recording medium described in Japanese Patent Laid-Open Publication No. Hei 11-911936, address information is recorded on a reflective surface of the reflective substrate outside the hologram layer.
When address information is recorded in a hologram layer as described in Japanese Patent Laid-Open Publication No. 2002-251745, there is the problem that the addressing operation becomes complicated.
When address information is recorded outside a hologram layer as described in Japanese Patent Laid-Open Publication No. Hei 11-311936, there is the problem that a positional error between the hologram and address information tends to occur.